Sounds like a playback issue for the media files it tests with. The media files are located in windows\performance\winsat

In that folder, you will see media files with extensions .mp4, .mpg, .wmv. In these container formats are HD Mpeg2, 480i & 480p Mpeg2, VC1, and h264. How do I know this? its in the filenames

Firstly make sure the files are actually there and you haven't deleted them as 'junk files'! There should be six files starting with 'clip_'. There should also be 5 files starting with 'shader', winsat.prx, and two more .wmv files starting with 'winsat'. If you are viewing these files in Windows explorer, make sure you disable the 'hide extensions for known file types' option under 'organise --> File and folder options --> View tab. The reason why you want to do this is because for one, its a stupid thing in my opinion to hide the extension, and two, you know exactly what you're opening! (especially for file types such as media files that all use the same icon, aka the player icon). Try playing each of those files back and see if they all play properly. If so, your problem may be a third party codec that has assumed decoding control on one of those formats, and even though it may decode fine, may not be compatible with Winsat...

You can use winsat from the command prompt, although I'm not sure how to use the media options with it! But you can type on 'winsat mem' and it will benchmark your memory in MB/s, 'winsat cpu -compression' etc is another option, and so on.